--------------------------------------------------------------------------------Version 0.95 (Release date: 4.11.2007)! Fixed GDI leak under Windows 9x/ME. Could lead to a crash after frequent updates of the coordinatesystem.--------------------------------------------------------------------------------Version 0.94 (Release date: 6.11.2005)Executable renamed from wz_grapher.exe to wzgrapher.exe+ Supports graphs in polar coordinates, also for ordinary differential equations.+ Mousegesture duration no longer infinite (now 1.5 seconds).+ Detailed main help can now be invoked directly from function input dialogs (per F1 key).+ Changes to axes titles can be applied immediately, while the dialog is still open.+ Messagebox that requests confirmation if user changes default values for x- and y-range.+ Up to 1024 scroll/zoom undo steps.* Rendering of coordinatesystem is worlds faster, especially perceptible when also subgrid is displayed.* Drawing the zoom selection rectangle is faster (perceptible on slower machines).* Some improvements on the rendering modules for graphs and help windows.* Improvements on the printing engine (e.g. leaves margins).! Fixed: Parallel installed versions < 0.91 won't crash at startup anymore (this is actually a bug in those old versions, the new version just doesn't "uncover" it anymore).! Regression: Results y of cot(x) were offset by -pi.--------------------------------------------------------------------------------Version 0.93 (Release date: 4.5.2005)+ New: Derivative operator d(). Computes the derivative of the expression within the parentheses. Examples: y=d(x^2) or y=1/12*d(d(x^4)). Supported maximum nesting level is 3 (allows to compute up the 3. derivative).+ Main dialogs and thus function input textedits can be resized horizontally. The app now remembers these sizes and positions also when being restarted.+ Main and help window can be KDE-like dragged by simultaneously pressing the ALT key.+ Accuracy of drawn integral solution curves further improved through pixel alignment of the lower integration limit.+ Zoom functionality regards whether the concerned range (x or y) is displayed in units of PI.- Select box "Draw 1. derivative" on the dialog for normal functions removed. The new derivative operator d() has made this option needless.! Single-value-calculator bug from V. 0.92.7 was not yet properly fixed, did occasionally evaluate y' to false infinite.! Fixed: Resizing the function input dialog vertically didn't work properly.! When selecting a zooming rectangle, stretching the rectangle beyond the left window boundary didn't work correctly.--------------------------------------------------------------------------------Version 0.92.9 (Release date: 15.4.2005)Parts of core code rewritten, e.g. the coordinate system engine and thefunctions for formatting and drawing numbers.+ Draws now also sub-tickmarks.--------------------------------------------------------------------------------Version 0.92.8 (Release date: 24.3.2005)+ Graph image copied to clipboard via CTRL+C is now also GIMP-compatible. Consider that in GIMP you cannot paste external data from the clipboard via CTRL+V; use "Edit"->"Paste From Clipboard" instead.+ Mousecoordinates-tooltip can display values in units of Pi.! Fixed: Selecting a zooming rectangle with the mouse could not be canceled by pressing [Esc].! Bug introduced with v 0.92.7: Single-value function calculator did not always print the first derivative value and could occasionally crash.- Zoom functionality of help windows disabled (didn't work properly with some video cards - I'll try to fix that later).--------------------------------------------------------------------------------Version 0.92.7 (Release date: 20.3.2005)+ Draws optionally also the 1. derivative, of normal functions as well as of ordinary differential equations.+ ODE-solving function calculator: Inserts initial values into the value tables when these are copied to the clipboard.+ Supports XP styles (themes) when running on Windows XP.--------------------------------------------------------------------------------Version 0.92.6 (Release date: 6.3.2005)+ Improved file name handling, e.g. filename is now set to "untitled.wzg" if not yet userspecified.! Fixed: Out-of-bounds memory reading could occur with binary files corrupted in a certain manner (missing zero-bytes in ascii section of file).--------------------------------------------------------------------------------Version 0.92.5 (Release date: 28.2.2005)* Coordinates at mousepointer displayed also while selecting a zoom rectangle.* Zoom selection rectangle entirely visible also when expanded beyond the app's window boundaries.--------------------------------------------------------------------------------Version 0.92.4 (Release date: 25.2.2005)+ Can be run from Startmenu/Execute (via command wz_grapher.exe, optionally with WZG file as parameter)* Function calculators for both normal functions and differential equations in same tabbed dialog.* Context menus for function-input dropdownboxes.* Improved memory management, again slightly less memory usage.! Occasionally false singularity recognitions when rendering functions which are difficult to graph, such as sin(1/x).--------------------------------------------------------------------------------Version 0.92.3 (Release date: 11.2.2005)+ Helperfunction sqr( ) squares argument.--------------------------------------------------------------------------------Version 0.92.2 (Release date: 9.2.2005)! Fixed: Crash if multiple instances were running and the function input dialog of another instance was open when WZ.Grapher was closed.! Bug regression from v.0.92 fixed: GDI leak when axes titles were displayed.--------------------------------------------------------------------------------Version 0.92.1 (Release date: 9.2.2005)* Numerical integration: Improved handling of incontinuousities if lower integration limit x0 is less than x min, i.e. outside of displayed x range.* Slightly faster rendering speed when displaying integrals.--------------------------------------------------------------------------------Version 0.92 (Release date: 5.2.2005)+ Coordinatesystem either crossed or boxed style. Tickmark labels can be toggled independently from the coordinatesystem style.+ Titles for axes user-renameable. Axes titles are also saved to WZG files.! Black background was printed in grey.--------------------------------------------------------------------------------Version 0.91.6 (Release date: 28.1.2005)+ Enhanced contrast of visualized integral area.--------------------------------------------------------------------------------Version 0.91.5 (Release date: 26.1.2005)+ Can save graph images as GIF (up until now as BMP only).--------------------------------------------------------------------------------Version 0.91.1 (Release date: 16.1.2005)! Crashed on WinXP when started the first time after installation from a useraccount without admin rights.! Function parser didn't recognize as syntax error the second argument of a two-arguments helperfunction being displaced into a following one-argument function.--------------------------------------------------------------------------------Version 0.91 (Release date: 10.1.2005)+ "Undo" functionality for zoom and scroll actions, with up to 200 undo steps. Also, the "Undo" menu entry classifies the type of action (e.g. "Undo: Scroll").+ Mousewheel support: Help windows - scroll; main window - zoom in, zoom out centered on position of mouse cursor.+ Text of help windows can be zoomed in and out via menu or keyboard.+ The "Save File?" messagebox that comes up when the application is about to be terminated can now be disabled.+ Option to reset all preferences and settings ("Options"->"Reset All Settings").* Behaviour of zooming by vertical mouse gesture changed: now zooming is centered on position of the cursor (same behaviour as with zooming by mousewheel), rather than moving the point underneath the cursor to the window center.- Command line option for initial window size removed (WZ.Grapher remembers last window size instead).--------------------------------------------------------------------------------Version 0.90.1 (Release date: 28.12.2004)+ gamma() function: increased precision, particularly with arguments less than 1.0.+ Toolbar button to toggle visibility of coordinate system border--------------------------------------------------------------------------------Version 0.90 (Release date: 21.12.2004)+ WZ.Grapher now remembers mathematical expressions filled into inputs for numerical values (x min etc.). Up until now, WZ.Grapher 'forgot' these expressions and showed their decimalpoint equivalents when a dialog came up again.+ Changed file format which remembers the above mentioned expressions for numerical inputs.+ Can now calculate both in radians and degrees angular mode.+ Improved syntax error handling of input expressions, such as: Now the user is notified when he uses a comma instead of a period as decimal point. Earlier versions just ignored the digits after the comma, such truncating the number to integer.+ When terminated, WZ.Grapher saves the current user settings (to INI file) and re-uses them when being started the next time.Iconspicious improvements, such as:+ Default x and y range values can be altered from within input dialogs.+ Number of running instances of WZ.Grapher can optionally be limited to one.+ When going to be closed, WZ.Grapher now asks the user whether other running instances should also be terminated.! Under Win 9x, when an expression syntax error was detected, the concerned input dialog box was occasionally dublicated.! Could under some circumstances be crashed by zooming via keybord while the mouse was on a toolbar button with the button's tooltip being displayed--------------------------------------------------------------------------------Version 0.88.2 (Release date: 1.12.2004)+ Coordinate system grid, ticks and labels can be displayed in units of Pi--------------------------------------------------------------------------------Version 0.88.1 (Release date: 5.11.2004)+ Content of Help windows can now be printed* Enhanced stack protection* Several internal optimizations--------------------------------------------------------------------------------Version 0.88 (Release date: 19.10.2004)+ Improved file handling: Now the surfaces for functions, integrals and differential equations each can load, display and handle files independently from each other+ When displaying an integral curve, WZ.Grapher now visualizes the integration area below the integrand by filling it with light-blue+ First experiments to provide import capabilities for files from other graphing programs: Can import Equation Grapher (.EGR) files* Minor modifications on how the coordinate system is displayed--------------------------------------------------------------------------------Version 0.87.1 (Release date: 14.10.2004)+ Differential equation (ODE): The basic value and hence the solution curve are now exactly pixel-aligned => again increased precision of the drawn graph! Value table of ODE: Wrong results if the x0 of the basic value, as specified by the user, was not x-step-aligned, for example: wrong result if x min = -5.0, x max = 5.0, x step width = 0.5, x0 = 1.25 (not x-step-aligned). Yes, now the basic value may be placed anywhere between x min and x max, independently from the x step width--------------------------------------------------------------------------------Version 0.87 (Release date: 12.10.2004)+ Can compute value tables of ordinary differential equations (ODE); like those for normal functions, these value tables contain also the first-derivative values+ Can numerically solve up to fifth-order ODE+ Numerical integration between 20% and 70% faster! Dotted subgrid lines appear now also dotted when printed--------------------------------------------------------------------------------Version 0.86.3 (Release date: 30.9.2004)+ Solving differential equations: Again increased precision (independendly from the order of the ODE), in "High Precision" mode 30% faster! Integral dialog: Under certain though not very probable conditions, one or more of the function expressions within the dropdown list could be corrupt--------------------------------------------------------------------------------Version 0.86.2 (Release date: 23.9.2004)+ Graphs can be drawn into the main window directly from the function calculator dialogs! Zooming triggered by mousegestures wasn't correctly vertical-centered on the mousedown location--------------------------------------------------------------------------------Version 0.86.1 (Release date: 17.9.2004)+ Small modifications of the appearance of the coordinate system (e.g. togglable border)* Smarter detection of extrema at domain boundaries! Vertical zooming didn't work if y min and y max were not user-specified--------------------------------------------------------------------------------Version 0.86 (Release date: 16.9.2004)+ Can numerically solve up to fourth-order differential equations+ 50% faster and strongly increased precision with solving third-order differential equations--------------------------------------------------------------------------------Version 0.85.2 (Release date: 8.9.2004)* Subgrid not displayed by default! When solving a differential equation, the application could crash in case of the solution being undefined at the basic value (example: y'=x/y with y(x0) having been set to 0.0)! Wrong tooltips displayed on the dialog for differential equation input--------------------------------------------------------------------------------Version 0.85.1 (Release date: 7.9.2004)* Several inconspicious improvements on the function calculator--------------------------------------------------------------------------------Version 0.85 (Release date: 2.9.2004)+ Can numerically solve up to third-order differential equations+ Solving second-order differential equations 40% faster and with increased precision--------------------------------------------------------------------------------Version 0.84 (Release date: 27.8.2004)+ Integration: Now the starting point x0 of the integration interval is independent from the left boundary (x min) of the displayed x range => the integration can start anywhere inside (and to some degree even outside) of the visible range+ Input textboxes for numbers (e.g. x min) now accept mathematical expressions, provided these follow the rules for function expressions, such as pi * -asinh(2.5*ln10) or, more realistically, pi/2+ Factorial operator and function implemented+ Enhanced WZG files format which now saves additionally... 1.) ...with integrals, the lower limit (starting point) of the integration interval 2.) ...with differential equations, the basic value, i.e. the data of the point through which the solution curve must pass* Main grid lines slightly less accentuated, subgrid lines dashed => maingrid, subgrid, tickmarks and graphs should appear visually more distinct--------------------------------------------------------------------------------Version 0.83 (Release date: 17.8.2004)+ Extended differential equation solving capabilities: Now the basic value (the point through which the solution curve must pass) can be placed arbitrarily between x min and x max - contrary to the earlier versions of WZ.Grapher which could only solve initial value problems with the basic value at x min+ In the differential equation mode, now also normal functions (diff equs of the "zeroth order") can be entered. For example, y=x*sin(x) is as well accepted as y'=x*sin(y) or y''=xy*sin(y')+ Input textboxes for numbers (e.g. x min, x max etc.) now accept also the predefined constants (PI, E, LN2 etc.)--------------------------------------------------------------------------------Version 0.82.2 (Release date: 15.8.2004)+ Internal improvements on the differential equation solver engine (for example faster on first-order diff equs)! On rare occasions the application crashed when being terminated! Wrong integration results if the option "Absolute Integral" was selected (a bug regression from Version 0.82 on)--------------------------------------------------------------------------------Version 0.82.1 (Release date: 14.8.2004)* Further memory usage optimizations* Refinements on the coordinate system- Some, in my opinion, useless backgroundcolor options removed--------------------------------------------------------------------------------Version 0.82 (Release date: 12.8.2004)+ Function calculator can also evaluate a single value and it's derivative value+ Function calculator: Increased precision near infinite derivative values+ Context menu even for textedit boxes which are sensitive to mouse gestures+ Smarter recognition of whether a file has been changed and needs to be saved* Further inconspicious improvements! Application crashed when a valuetable computation was started with the function expression textbox being empty! Application could hang if the following three conditions coincided: 1.) double buffered video mode switched off 2.) the dialog for integration or differential equations was invoked the first time after application startup 3.) the dialog was moved across the main window--------------------------------------------------------------------------------Version 0.81 (Release date: 7.8.2004)+ frac() function implemented - returns the fractional part of it's argument+ Can calculate negative numbers to powers whose inverse numbers are odd integers+ Dropdown lists for function expressions now remember up to 20 functions* Discontinuosities of a function are now also recognized next to x min and x max (e.g. with ceil(x) and x min being -5, no longer a vertical line is drawn at x min)* Enhanced recognition of +-infinite derivative values when creating function value tables (e.g. sqrt(x) at x=0 or acos(x) at -1 and +1)! Dialog for function definitions didn't remember it's previous height => default height when re-opened--------------------------------------------------------------------------------Version 0.80.1 (Release date: 29.7.2004)+ Improvements on managing the statusbar text--------------------------------------------------------------------------------Version 0.80 (Release date: 29.7.2004)+ Can numerically solve differential equations of the first and second order+ Can generate function value tables, including the according derivative values. These tables can be straighly (buttonclick) copied to the clipboard and from there be pasted into Spreadsheet documents (Excel) etc.+ The graph window, more precisely the coordinate system, can now be made quadratic (via Ctrl+Q or menu)+ Accepts also a preceeding 'f(x)=' or 'y=' on function expressions. This should facilitate copying expressions from somewhere else into WZ.Grapher+ The integral sign displays the bottom limit of the integration interval* More toolbar buttons -> two toolbars instead of one! The drop-down list for integrand function expressions was a bit stupid: It tended to remember erroneous function expressions too easily, and did not always insert the most recently used entries on top of the list. Moreover, it now can't anymore be fooled by whitespaces within expressions

Despite the new features, the size of the application is still very small, just 189 kB, and memory usage is relatively frugal.--------------------------------------------------------------------------------Version 0.71 (Release date: 11.7.2004)+ Dialog for integral input contains a drop-down selection list for integrand function expressions (remembers up to 15 functions)! Application crashed when integration was started but the integrand input field was empty--------------------------------------------------------------------------------Version 0.70.3 (Release date: 9.7.2004)+ Some minor modifications on the appearance of the coordinate system. Particularly, tickmarks can now be toggled independently from other settings, are also drawn on the top and right side, and their thickness is dependent from the linewidth setting--------------------------------------------------------------------------------Version 0.70.2 (Release date: 9.7.2004)+ A few new minor additions, such as: The short guide that lists the helperfunctions and operators can also be called from the integral input dialog; 'Integration' in context menu--------------------------------------------------------------------------------Version 0.70.1 (Release date: 8.7.2004)* Improvements of the integration engine (e.g. recognizes better limits of the integration interval, i.e. where the integral becomes undefined versus where the integrand is discontinuous but it's definite integral not undefined).--------------------------------------------------------------------------------Version 0.70 (Release date: 7.7.2004)+ Numerical integration with high precision which accommodates automatically to screen resolution. Draws the integral curve.--------------------------------------------------------------------------------Version 0.62 (Release date: 29.6.2004)+ Four different colour profiles (background colours) can be picked* Again some performance tuning, some 5% faster* Modifications of the code to be better prepared for planned future extensions (such as calculating integrals)--------------------------------------------------------------------------------Version 0.61.1 (Release date: 26.6.2004)+ When the program starts, it displays an instruction how to enter functions* A few modifications of the Help Topics and their rendering engine--------------------------------------------------------------------------------Version 0.61 (Release date: 26.6.2004)+ Incomplete elliptic integrals of first and second kind implemented+ Again slightly faster--------------------------------------------------------------------------------Version 0.60 (Release date: 25.6.2004)+ Capable to print+ Complete elliptic integrals of first and second kind implemented+ Remembers last open/save directory independently from the Windows version+ Subgrid visibility can be toggled* Higher subgrid resolution, i.e. smaller subgrid divisions* Extended automatic menu item disabling/enabling* Improved color management on devices with less-than-24-bit color depth--------------------------------------------------------------------------------Version 0.55 (Release date: 5.6.2004)+ The graph-picture can now be copied (either as scalable metafile or as bitmap) to the clipboard, and hence be pasted into other programs such as office suites (for instance OpenOffice, Word or Excel documents) or graphics programs (Corel etc.)+ Can save preferences (to INI file)* Many under-the-hood improvements, such as: The graphics mode switches automatically from doublebuffered to non-doublebuffered mode in case there's not enough videomemory available (too many instances or other programs open, particularly with maximized windows). Re-switches automatically to doublebuffered mode once memory is detected to be sufficient again- Sound removed (I just felt so and might occasionally switch my mind again)--------------------------------------------------------------------------------Version 0.52 (Release date: 29.5.2004)+ Gamma function implemented--------------------------------------------------------------------------------Version 0.51.1 (Release date: 29.5.2004)* Improved recognition of earlier versions on the system--------------------------------------------------------------------------------Version 0.51 (Release date: 27.5.2004)+ Now WZG files (WZ.Grapher files) are automatically associated with the program when it is started the first time+ Additional command line option: Path of file to be loaded at startup--------------------------------------------------------------------------------Version 0.50 (Release date: 23.5.2004)+ WZG file-type is now binary and saves the preferences which concern the look of the coordinate system and graphs (the new WZG type is NOT compatible with the previous text-mode one)+ gaussd() function (Gaussian Bell Curve function) implemented+ Bells and Whistles: Play sound when graphs are drawn (can be toggled via "Options" menu)+ New exponentiation operator besides the already existing base^exponent, base"exp., base'exp. and p(base,exp.) supported: **, for example x**2* Again about 25% faster! Drag&Dropping a .WZG file on the application now brings the window automatically to the foreground! The undocumented but nevertheless supported base² and base³ exponentiation notations shouldn't be able to cause crashs anymore--------------------------------------------------------------------------------Version 0.44 (Release date: 20.5.2004)+ Statusbar (can be toggled) implemented--------------------------------------------------------------------------------Version 0.43.9 (Release date: 18.5.2004)* Modified subgrid algorithm - subgrid ticks more precisely positioned* Ask-about-save dialog now comes up in case the application is to be closed and graphs have been changed--------------------------------------------------------------------------------Version 0.43.8 (Release date: 12.5.2004)! Bug regression from version 0.43.7 fixed: GDI leak.--------------------------------------------------------------------------------Version 0.43.7 (Release date: 10.5.2004)+ Sub-grid added to coordinate system+ E-Mail hyperlink implemented in the application's "About" dialog* Improved division processing. Example: With f(x) being 1/(-x^2), lim x->0 f(x) yields now correctly -infinite rather than +infinite! Checking/unchecking the menuitem "Mouse Coordinates" in context menu works now correctly--------------------------------------------------------------------------------Version 0.43.6 (Release date: 2.5.2004)! Pipes used as operators for absolute values, example: -1*sin(|x|), can't crash the application anymore--------------------------------------------------------------------------------Version 0.43.5 (Release date: 22.4.2004)+ Hyperlink to www.walterzorn.de/www.walterzorn.com from the application's "About" dialog! "Help Contents" text in english version corrected: Shortcut for toggling the visibility of function expressions is "E", rather than "T" as in the german version--------------------------------------------------------------------------------Version 0.43 (Release date: 21.4.2004)+ New helper function: atan2